Air quality
About the Air quality PCB
Air quality is an open source ESP8266 PCB design by NilsEngelbach, published on GitHub. It is a 2-layer board measuring 72 × 72 mm, with 65 components from 39 distinct parts.
Its main chip is the ESP-12F, from the ESP8266 family. Other key parts include the CP2102N-A02-GQFN28, MCP73831T-2ACI/OT, AP2112K-3.3TRG1, BME688 and USBLC6-2SC6. By type, the board carries 22 resistors, 19 capacitors, 7 ICs, 4 transistors, 4 connectors and 4 diodes.
It belongs with the sensors, power & battery and dev boards & breakouts designs in this gallery, and the repository also holds 4 earlier revisions of it.
From the project
Custom 2-layer KiCad board for the air-quality-checker firmware: an ESP8266 air-quality monitor that reads a Bosch BME688 over I2C and moves an SG92R micro servo to indicate the current IAQ level. Battery-powered with LiPo charging over USB-C.
Custom 2-layer KiCad board for the air-quality-checker firmware: an ESP8266 air-quality monitor that reads a Bosch BME688 over I2C and moves an SG92R micro servo to indicate the current IAQ level. Battery-powered with LiPo charging over USB-C.
This board replaces the Adafruit Feather HUZZAH with an on-board design, so the whole system fits on one PCB.
Board size: 108 × 108 mm, 2 copper layers, 1.6 mm FR4.
Main components on the Air quality
Air quality bill of materials (BOM)
65 components, 39 distinct parts — part numbers from the project's BOM.
| Qty | Part | Footprint | Refs |
|---|---|---|---|
| 1 | ESP-12F Ai-Thinker | ESP-12E | U1 |
| 1 | CP2102N-A02-GQFN28 Silicon Labs | QFN-28-1EP_5x5mm_P0.5mm_EP3.35x3.35mm | U2 |
| 1 | MCP73831T-2ACI/OT MCP73831 Microchip Technology | SOT-23-5 | U3 |
| 1 | AP2112K-3.3TRG1 AP2112K-3.3 Diodes Incorporated | SOT-23-5 | U4 |
| 1 | BME688 Bosch Sensortec | Bosch_LGA-8_3x3mm_P0.8mm_ClockwisePinNumbering | U5 |
| 1 | USBLC6-2SC6 STMicroelectronics | SOT-23-6 | U6 |
| 1 | MT3608 Aerosemi Tech | SOT-23-6 | U7 |
| 2 | MMBT2222ALT1G MMBT2222A onsemi | SOT-23 | Q1, Q2 |
| 2 | DMG2305UX-7 DMG2305UX Diodes Incorporated | SOT-23 | Q3, Q4 |
| 1 | TYPE-C-31-M-12 USB-C Korean Hroparts (HRO) | USB_C_Receptacle_HRO_TYPE-C-31-M-12 | J1 |
| 1 | 61300311121 SERVO Wurth Elektronik | PinHeader_1x03_P2.54mm_Vertical | J3 |
| 1 | B2B-PH-K-S LiPo JST | JST_PH_B2B-PH-K_1x02_P2.00mm_Vertical | J4 |
| 1 | 61300411121 SPARE Wurth Elektronik | PinHeader_1x04_P2.54mm_Vertical | J5 |
| 1 | DEEPSLEEP | SolderJumper-2_P1.3mm_Bridged_Pad1.0x1.5mm | JP1 |
| 1 | KMR221G LFS RESET C&K | SW_Push_1P1T_NO_CK_KMR2 | SW1 |
| 1 | KMR221G LFS BOOT C&K | SW_Push_1P1T_NO_CK_KMR2 | SW2 |
| 1 | PCM12SMTBR POWER C&K | SW_SPDT_PCM12 | SW3 |
| 1 | B5819W-TP B5819W MCC (Micro Commercial Components) | D_SOD-123 | D1 |
| 1 | LTST-C170GKT CHG-GREEN Lite-On Inc. | LED_0805_2012Metric | D2 |
| 1 | LTST-C170TBKT STATUS Lite-On Inc. | LED_0805_2012Metric | D3 |
Show 19 more
| Qty | Part | Footprint | Refs |
|---|---|---|---|
| 1 | SS34-HF SS34 Comchip Technology | D_SMA | D4 |
| 1 | SWPA4030S100MT 10uH Sunlord | L_Sunlord_SWPA4030S | L1 |
| 8 | CL21B104KBCNNNC 100nF Samsung Electro-Mechanics | C_0805_2012Metric | C1, C3, C5, C8, C12, C14, C15, C17 |
| 4 | CC0805KRX5R7BB106 10uF YAGEO | C_0805_2012Metric | C2, C11, C16, C18 |
| 4 | CL21A475KOFNNNG 4.7uF Samsung Electro-Mechanics | C_0805_2012Metric | C4, C6, C7, C9 |
| 1 | CL21B105KOFNNWE 1uF Samsung Electro-Mechanics | C_0805_2012Metric | C10 |
| 1 | UCD1C101MCL1GS 100uF Nichicon | CP_Elec_6.3x5.4 | C13 |
| 1 | CL21A226KOQNNNG 22uF Samsung Electro-Mechanics | C_0805_2012Metric | C19 |
| 9 | RC0805FR-0710KL 10k YAGEO | R_0805_2012Metric | R1, R2, R3, R4, R5, R6, R7, R18 +1 |
| 2 | RC0805FR-07100KL 100k YAGEO | R_0805_2012Metric | R9, R20 |
| 2 | RC0805FR-075K1L 5.1k YAGEO | R_0805_2012Metric | R10, R11 |
| 1 | RC0805FR-0722K1L 22.1k YAGEO | R_0805_2012Metric | R12 |
| 1 | RC0805FR-0747K5L 47.5k YAGEO | R_0805_2012Metric | R13 |
| 1 | RC0805FR-072K2L 2.2k YAGEO | R_0805_2012Metric | R14 |
| 2 | RC0805FR-071KL 1k YAGEO | R_0805_2012Metric | R15, R16 |
| 1 | RC0805FR-07100RL 100R YAGEO | R_0805_2012Metric | R17 |
| 1 | RC0805FR-0727KL 27k YAGEO | R_0805_2012Metric | R21 |
| 1 | RC0805FR-0782KL 82k YAGEO | R_0805_2012Metric | R22 |
| 1 | RC0805FR-0711KL 11k YAGEO | R_0805_2012Metric | R23 |
Air quality design files
The KiCad project lives in the NilsEngelbach/air-quality-pcb repository on GitHub; these links point at the commit this page was built from.
Air quality: common questions
What microcontroller does the Air quality use?
The Air quality is built around the ESP-12F, from the ESP8266 family.
How big is the Air quality PCB?
The Air quality measures 72 × 72 mm, has 2 copper layers and is 1.6 mm thick.
How many components are on the Air quality?
65 components, from 39 distinct parts, with part numbers taken from the project's own BOM. The full bill of materials is listed on this page.
Where can I download the Air quality design files?
From the NilsEngelbach/air-quality-pcb repository on GitHub, which has the KiCad layout, the schematic and the BOM; the links under Design files point to each one.
Can I use the Air quality design in my own project?
The repository has no license, so all rights stay with NilsEngelbach. Use it as a reference, and ask the author before reusing the design.
Can I test firmware for the Air quality without the hardware?
Yes. HardLabs builds a simulation of the board from its netlist and BOM, so you can run and debug ESP8266 firmware against it before you order a PCB.
Earlier revisions in the repo: air-quality-pcb-v4, air-quality-pcb-v3, air-quality-pcb-v2, air-quality-pcb
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